Non-invasive skin measurement methods and diagnostics for vitiligo: a systematic review

Vitiligo is a multifaceted autoimmune depigmenting disorder affecting around 0.5 to 2.0% of individuals globally. Standardizing diagnosis and therapy tracking can be arduous, as numerous clinical evaluation methods are subject to interobserver variability and may not be validated. Therefore, there is a need for diagnostic tools that are objective, dependable, and preferably non-invasive.

Aims

This systematic review provides a comprehensive overview of the non-invasive objective skin measurement methods that are currently used to evaluate the diagnosis, severity, and progression of vitiligo, as well as the advantages and limitations of each technique.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist was used for the systematic review. Scopus, Embase, Cochrane Library, and Web of Science databases were comprehensively searched for non-invasive imaging and biophysical skin measuring methods to diagnose, evaluate the severity of, or monitor the effects of vitiligo treatment. The risk of bias in included articles was assessed using the QUADAS-2 quality assessment scale.

Results

An extensive literature search resulted in 64 studies for analysis, describing eight imaging techniques (reflectance confocal microscopy, computer-aided imaging analysis, optical coherence tomography, infrared photography, third-harmonic generation microscopy, multiphoton microscopy, ultraviolet light photography, and visible light/digital photograph), and three biophysical approaches (dermoscopy, colorimetry, spectrometry) used in diagnosing and assessing vitiligo. Pertinent information about functionality, mechanisms of action, sensitivity, and specificity was obtained for all studies, and insights into the strengths and limitations of each diagnostic technique were addressed. Methodological study quality was adequate; however, statistical analysis was not achievable because of the variety of methods evaluated and the non-standardized reporting of diagnostic accuracy results.

Conclusions

The results of this systematic review can enhance clinical practice and research by providing a comprehensive overview of the spectrum of non-invasive imaging and biophysical techniques in vitiligo assessment. Studies with larger sample sizes and sound methodology are required to develop verified methods for use in future practice and research.

Systematic review registration

(PROSPERO) database, (CRD42023395996).

Non-Invasive Biomarkers in Saliva and Eye Infrared Thermography to Assess the Stress Response of Calves during Transport

Animal transport is currently a stressful procedure. Therefore, animal-based indicators are needed for reliable and non-invasive welfare assessment. Saliva is a biospecimen with potential validity for the determination of cortisol and oxidative stress, although its use to assess calf welfare during transport has never been tested. Similarly, the applicability and reliability of infrared thermography to assess temperature change during calves' transport have never been evaluated. These objectives were outlined following the known and growing need to identify non-invasive methodologies for stress assessment in bovines. This study was conducted on 20 calves of the Arouquesa autochthone breed, at about nine months of age, during their transport to slaughter. For each animal, saliva samples and thermographic images of the eye were collected at three time points: before transport, after transport, and at slaughter. The saliva was then processed to measure cortisol levels and oxidative stress parameters (reactive oxygen species, thiobarbituric acid reactive substance, carbonyls, and advanced oxidation protein products), and the images were analyzed using FLIR Tools+ software. There was an increase in cortisol concentration and oxidative stress parameters (reactive oxygen species, thiobarbituric acid reactive substance, carbonyls, and advanced oxidation protein products) in saliva after transport. An increase in eye temperature triggered by transport was also observed. The cortisol and eye temperature results at slaughter were returned to values similar to those before transport; however, the values of oxidative stress remained increased (mainly TBARS values). These non-invasive techniques seem to be reliable indicators of stress in bovine transport, and oxidative stress parameters in saliva may be a persistent marker for welfare assessment.

Analytical Investigations of XIX-XX Century Paints: The Study of Two Vehicles from the Museum for Communications of Frankfurt

Over the centuries, humans have developed different systems to protect surfaces from the influence of environmental factors. Protective paints are the most used ones. They have undergone considerable development over the years, especially at the turn of the 19th and 20th centuries. Indeed, between the two centuries, new binders and pigments have been introduced in the constituent materials of paints. The years in which these compounds have been introduced and spread in the paint market allow them to be defined as markers for the dating of paints and painted artifacts. The present work is focused on the study of the paints of two vehicles of the Frankfurt Museum of Communication, i.e., a carriage and a cart, that was designed for the German Postal and Telecommunications Service roughly between 1880 and 1920. The characterization of the paints was performed through in situ non-invasive techniques, i.e., portable optical microscopy and multispectral imaging, and laboratory non-destructive techniques, i.e., FT-IR ATR spectroscopy and SEM-EDS. The analytical investigation and the comparison with the data reported in the literature allowed us to determine the historicity of the paints, which are all dated before the 1950s.

Unusual Dermoscopic Patterns of Basal Cell Carcinoma Mimicking Melanoma

Background

Basal cell carcinoma can simulate melanoma and specific dermoscopic criteria have not yet been defined in a large cohort.

Objective

To identify dermoscopic “trump” characteristics for differential diagnosis, identify cluster groups and assess the clinical impact of this study's findings.

Methods

Retrospective, multicentric comparative study of atypical, non‐facial basal cell carcinoma (≥1 seven‐point checklist criteria) and melanoma (with at least one BCC criteria) at dermoscopy. Observed dermoscopic features were used to develop a proposed score. Lesion clusters were defined with hierarchical analysis. Clinical impact was assessed with a blinded reader study following this study's results.

Results

A total of 146 basal cell carcinoma and 76 melanoma were included. Atypical vascular pattern was common to most lesions (74.5%). Twelve trump features were included in the proposed score (sensitivity 94.1% and specificity 79.5%). Cluster analysis identified 3 basal cell carcinoma and 3 melanoma clusters. Findings improved overall diagnostic accuracy and confidence (26.8% and 13.8%, respectively; p < 0.001).

Conclusions

These findings support the notion that atypical vascular pattern should be considered a shared feature of both melanoma and atypical basal cell carcinoma. Our proposed score improves diagnostic accuracy and confidence. Absence of pigmented features was associated with lower diagnostic accuracy and confidence.

Case Report: Amyloidosis Cutis Dyschromica: Dermoscopy and Reflectance Confocal Microscopy and Gene Mutation Analysis of a Chinese Pedigree

Background: Amyloidosis cutis dyschromica (ACD) is a rare type of primary localized cutaneous amyloidosis. Non-invasive techniques can provide important clues for early diagnosis. Objectives: To highlight the characteristic imaging changes of ACD under dermoscopy and reflectance confocal microscopy (RCM), investigate gene mutations in a Chinese Han pedigree of ACD, and analyze the genotype-phenotype correlation. Methods: Dermoscopy and RCM examinations were completed together for the pedigree, and the imaging characteristics were described. The diagnosis of ACD was confirmed by pathological examination. Sequencing was performed followed by bioinformatics and genotype-phenotype correlation. ACD-related articles published on PubMed between January 1970 and March 2021 were reviewed and summarized. Results: In ACD, dermoscopy showed patchy white hypopigmentation and brownish spots, stripes, or hyperpigmented blotches and patches. RCM showed a highly refractive substance with clumpy, dotted, and linear structures inside the papillary dermis. Sequencing identified glycoprotein non-metastatic melanoma protein B (GPNMB) missense mutations [c.393T>G (p.Y131X; NM_001005340.2)] and a frameshift deletion mutation [c.719_720delTG (p.V240fs; NM_001005340.2)]. The ANNOtate VARiation (ANNOVAR) software predicted that c.393T>G is a pathogenic mutation. The literature review found 14 mutations, namely, 5 (35.7%) frameshift mutations, 4 (28.6%) non-sense mutations, 4 (28.6%) missense mutations, and 1 (7.1%) splice site mutation. Blisters and epidermolysis were observed in several cases, but there was no significant association between clinical manifestations and mutations in ACD. Conclusions: This study was the first to combine dermoscopy and RCM to describe ACD. Two GPNMB gene mutations were reported in a Chinese ACD pedigree. The genotype-phenotype correlation was analyzed for the first time; however, there was no significant correlation.

Non-invasive evaluation of subjective sensitive skin by transcriptomics using mRNA in skin surface lipids

Sensitive skin is a condition characterized by hypersensitivity to environmental stimuli, and its pathophysiology has not been fully elucidated. Questionnaires based on subjective symptoms, intervention tests, and measuring devices are used to diagnose sensitive skin; however, objective evaluation methods, including biomarkers, remain to be established. This study aimed to investigate the molecular profiles of self-reported sensitive skin, understand its pathophysiology and explore its biomarkers. Here, we analysed RNAs in skin surface lipids (SSL-RNAs), which can be obtained non-invasively by wiping the skin surface with an oil-blotting film, to compare the transcriptome profiles between questionnaire-based "sensitive" (n = 11) and "non-sensitive" (n = 10) skin participants. Exactly 417 differentially expressed genes in SSL-RNAs from individuals with sensitive skin were identified, of which C-C motif chemokine ligand 17 and interferon-γ pathways were elevated, while 50 olfactory receptor (OR) genes were downregulated. The expression of the detectable 101 OR genes was lower in individuals with sensitive skin compared to that in those with non-sensitive skin and was particularly associated with the subjective sensitivity among skin conditions. The receiver operating characteristic (ROC) curve demonstrated that the mean expression levels of OR genes in SSL-RNAs could discriminate subjective skin sensitivity with an area under the ROC curve of 0.836. SSL-RNA profiles suggest a mild inflammatory state in sensitive skin, and overall OR gene expression could be a potential indicator for sensitive skin.

A counterpoint paper: Comments on the electrocardiographic part of the 2018 Fourth Universal Definition of Myocardial Infarction endorsed by the International Society of Electrocardiology and the International Society for Holter and Noninvasive Electrocardiology

The Fourth Universal Definition of Myocardial Infarction (FUDMI) focuses on the distinction between nonischemic myocardial injury and myocardial infarction (MI), along with the role of cardiovascular magnetic resonance, in order to define the etiology of myocardial injury. As a consequence, there is less emphasis on updating the parts of the definition concerning the electrocardiographic (ECG) changes related to MI. Evidence of myocardial ischemia is a prerequisite for the diagnosis of MI, and the ECG is the main available tool for (a) detecting acute ischemia, (b) triage, and (c) risk stratification upon presentation. This review focuses on multiple aspects of ECG interpretation that we firmly believe should be considered for incorporation in any future update to the Universal Definition of MI.

The clinical significance of premature atrial contractions: How frequent should they become predictive of new-onset atrial fibrillation

Background

Although previous studies reported frequent premature atrial contractions(fPACs) increased the risk of adverse cardiovascular outcomes, especially atrial fibrillation(AF), there is a substantial inconsistency between reports concerning the definition of fPAC. In this study, we aimed to investigate the relationship between fPAC and cardiovascular outcomes, especially AF. We further searched for a cutoff value of fPAC for prediction of AF.

Methods

We retrospectively analyzed the ambulatory 24‐hr Holter monitoring records and 392 patients included. Frequent PAC was defined as more than 720 PAC/24 hr as used for frequent ventricular premature beats. Patients’ baseline characteristics, echocardiographic variables and medical history were recorded.

Results

There were 189 patients with fPAC and 203 patients without fPAC. Patients with fPAC had more comorbidities in terms of hypertension, diabetes mellitus, coronary artery disease and congestive heart failure. CHA2DS2‐VaSc was higher in patients with fPAC. Mean follow‐up duration was 31 months, and the number of patients with new‐onset AF during follow‐up was significantly higher in fPAC group (22% vs. 5%, p < .001). fPAC was significantly and independently associated with new‐onset AF and predicted AF with a cutoff value of 3,459 PAC/24 hr, and the risk of AF was 11‐fold higher than those with <3,000 PAC/24 hr. In addition, an increased CHA2DS2‐VaSc score was also associated with new‐onset atrial fibrillation.

Conclusion

In our study, we have demonstrated that fPAC is significantly associated with new‐onset AF, and this association is the strongest among those patients who have more than 3,000 PAC in 24 hr.

Magnetocardiography for identification of coronary ischemia in patients with chest pain and normal resting 12-lead electrocardiogram

Background

Identification of coronary ischemia in patients presenting with chronic chest pain is difficult as resting ECG can be normal. Diagnosis of coronary ischemia requires evaluation during exercise or pharmacological stress. A noninvasive test to identify coronary ischemia at rest without the need for exercise is desirable. We studied the diagnostic accuracy of magnetocardiography (MCG) at rest to detect coronary ischemia in these patients.

Methods

Patients with chronic chest pain and suspected coronary ischemia with a normal ECG were included. Patients underwent treadmill test (TMT) and were divided into TMT positive and TMT negative groups. MCG was recorded in a magnetically shielded room. Iso‐field contour maps generated at the T‐wave peak were compared between the groups. From the magnetic field map (MFM), the magnetic field angle at T‐wave peak was calculated and was also compared across the two groups.

Results

There were a total of 29 patients, 12 with positive TMT and 17 with negative TMT. An abnormal magnetic field angle was more common in the TMT positive group (72% vs. 6%). Abnormal contour maps in the form of nondipole patterns or abnormal orientation were seen in 81.8% (9/11) patients in TMT positive group and 6.8% (1/17) patients in the TMT negative group (p < .001).

Conclusion

Abnormal magnetic field angle and abnormal magnetic field maps in MCG recorded at rest are able to identify the presence of coronary ischemia in patients with chronic chest pain and a normal resting ECG.

Hepatitis C virus (HCV) related liver fibrosis in people who inject drugs (PWID) at the Stockholm Needle Exchange - evaluated with liver elasticity

Background and aims: Sharing of unsterile injection equipment among people who inject drugs (PWID) is the major transmission-route for hepatitis C (HCV). HCV is highly prevalent in PWID in the Stockholm needle exchange programme (NEP). The frequency of advanced liver fibrosis among the participants is, however, unknown. Methods: From December 2016 to April 2018, all participants with chronic hepatitis C infection (CHC) were offered liver fibrosis evaluation at the Stockholm NEP, including liver stiffness measurement (LSM), a medical history and expanded blood tests to evaluate APRI and FIB-4 scores. Results: A total of 2037 individuals were enrolled of whom 964 (47.3%) had CHC. LSM was performed in 203 (21.1%) of eligible participants of whom 85% had mild fibrosis (LSM ≤9.4 kPa) and 15% advanced fibrosis (LSM ≥9.5 kPa). APRI >1 and FIB-4 > 3.25 only identified 30% of participants with advanced fibrosis. However, all 31(100%) participants with advanced fibrosis were detected when APRI >1 was combined with an age of ≥40 years and an injection drug use (IDU) duration of ≥15 years. Conclusions: We found that the diagnostic work-up for advanced fibrosis can be simplified with this combination of easily available factors. This allows identification of PWID in need of immediate HCV treatment to prevent further disease progression. Furthermore, LSM can be avoided among PWID with mild fibrosis, identified by age <40 years combined with IDU duration of <15 years and APRI score <1. This strategy enhances the HCV care cascade where LSM is not easily available, and will thus facilitate HCV treatment initiation.

Fecal glucocorticoid metabolites and assay validation: Stress response evaluation in captive brown howler monkeys (Alouatta clamitans)

BACKGROUND

The advent of non-invasive methods provides a powerful alternative to stress studies as the use of stressful handling techniques is no longer needed. However, many factors influence hormone metabolism such as sex, diet, and metabolic rate. Thus, validation should be species- and matrix-specific.

METHODS

To assess stress response in brown howler monkeys Alouatta clamitans, we adopted an ACTH challenge test and parallelism to provide physiological and laboratorial validation. Radioimmunoassay was used to measure fecal levels of corticosterone.

RESULTS AND CONCLUSIONS

All challenged animals presented a peak in fecal glucocorticoids levels the day after the treatment, while control animals did not. There were no significant sex differences, but females with infants had higher levels of corticosterone. Corticosterone levels showed parallelism to the standard curve of the diagnostics kit. Collectively, the data suggest that the method was validated and is useful for monitoring stress, thereby helping in conservation programs both in captivity and in the wild. Transit time information may be coupled with travel distance in seed dispersal studies.

Symptomatic arrhythmia in the form of multiple premature ventricular extrasystoles as the first symptom of polymyositis

Polymyositis (PM) is an autoimmune disease characterized by the involvement of multiple internal organs, including the cardiovascular system. The involvement of heart is observed in up to 75% of patients with PM. Conduction and rhythm disorders are one of the most common cardiological abnormalities in these patients. The presented clinical case is the patient where ventricular arrhythmia (in the form of multiple premature ventricular extrasystoles) was the first symptom of polymyositis.

Comparison of non-invasive tear film stability measurement techniques

BACKGROUND

Measurement of tear film stability is commonly used to give an indication of tear film quality but a number of non-invasive techniques exists within the clinical setting. This study sought to compare three non-invasive tear film stability measurement techniques: instrument-mounted wide-field white light clinical interferometry, instrument-mounted keratoscopy and hand-held keratoscopy.

METHODS

Twenty-two subjects were recruited in a prospective, randomised, masked, cross-over study. Tear film break-up or thinning time was measured non-invasively by independent experienced examiners, with each of the three devices, in a randomised order, within an hour.

RESULTS

Significant correlation was observed between instrument-mounted interferometric and keratoscopic measurements (p < 0.001) but not between the hand-held device and the instrument-mounted techniques (all p > 0.05). Tear film stability values obtained from the hand-held device were significantly shorter and demonstrated narrower spread than the other two instruments (all p < 0.05), while no significant differences were observed between the two instrument-mounted devices (all p > 0.05).

CONCLUSION

Good clinical agreement exists between the instrument-mounted interferometric and keratoscopic measurements but not between the hand-held device and either of the instrument-mounted techniques. The results highlight the importance of specifying the instrument employed to record non-invasive tear film stability.

Airway inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an inflammatory airway disease whose incidence and mortality increases every year. It is associated with an abnormal inflammatory response of the lung to toxic particles or gases (usually cigarette smoke). A central role in the pathophysiology has been shown to play a chronic inflammation of the airways that is expressed primarily by hypersecretion of mucus, stenosis of the smaller airways and the establishment of pulmonary emphysema. There is an increasing trend for assessing the inflammatory pattern of inflammatory airway diseases through mediators measured by noninvasive techniques. Markers in biological fluids and exhaled air have been the subject of intense evaluation over the past few years, with some of them reaching their introduction into clinical practice, while others remain as research tools. Of particular interest for the scientific community is the discovery of clinically exploitable biomarkers associated with specific phenotypes of the disease. Studying the effects of therapeutic interventions in these biomarkers may lead to targeted therapy based on phenotype and this is perhaps the future of therapeutics in COPD.

Identifying individual common carp Cyprinus carpio using scale pattern

Volunteers were able to match photographs of the same common carp Cyprinus carpio taken on two occasions. Images were identified correctly on 95·76% of occasions. Thus, scale patterns can be used for non-invasive identification of C. carpio over a period of time.

The role of invasive and non-invasive procedures in diagnosing fever of unknown origin

BACKGROUND

The etiology of fever of unknown origin has changed because of the recent advances in and widespread use of invasive and non-invasive diagnostic tools. However, undiagnosed patients still constitute a significant number.

OBJECTIVE

To determine the etiological distribution and role of non-invasive and invasive diagnostic tools in the diagnosis of fever of unknown origin.

MATERIALS & METHODS

One hundred patients who were hospitalized between June 2001 and 2009 with a fever of unknown origin were included in this study. Clinical and laboratory data were collected from the patients' medical records retrospectively.

RESULTS

Fifty three percent of the patients were male, with a mean age of 45 years. The etiology of fever was determined to be infectious diseases in 26, collagen vascular diseases in 38, neoplastic diseases in 14, miscellaneous in 2 and undiagnosed in 20 patients. When the etiologic distribution was analyzed over time, it was noted that the rate of infectious diseases decreased, whereas the rate of rheumatological and undiagnosed diseases relatively increased because of the advances in imaging and microbiological studies. Seventy patients had a definitive diagnosis, whereas 10 patients had a possible diagnosis. The diagnoses were established based on clinical features and non-invasive tests for 61% of the patients and diagnostic benefit was obtained for 49% of the patients undergoing invasive tests. Biopsy procedures contributed a rate of 42% to diagnoses in patients who received biopsies.

CONCLUSION

Clinical features (such as detailed medical history-taking and physical examination) may contribute to diagnoses, particularly in cases of collagen vascular diseases. Imaging studies exhibit certain pathologies that guide invasive studies. Biopsy procedures contribute greatly to diagnoses, particularly for malignancies and infectious diseases that are not diagnosed by non-invasive procedures.